Process of making steel



. Patented Dec. i927.

JOSEPH KENT SMITH, or WORKSOI', ENGLAND, nssrenon, BY mnsnn-assremltnnrs,

T GBANULARIRON oomr'an'r, a oonr'onnrron or MICHIGAN.

' success or rice srnnn No Drawing.

This invention relates to a process for making steel on the. gas, oil, tar, or powdered coal fired open hearth, from solid produced Attempts-have been made to produce iron from iron bearing ores in the solid state, i. e., without melting and the literatureof the art contains many references to such attempts. Recently it has been discovered how iron may be solid produced in a practical ,com- .mercial manner.

Attempts to make steel from such produ'ct,.h0wever, have heretofore, in so far as I am aware, not met with success, probably because the nature of the product was notfully' understood. I The object of this invention is, therefore,

to provide amethod Whereby such solid pro duced iron may be effectively and economically converted into steel; and more spe-. cifically" it is an-object of the present invention to make possiblethe conversion of such solid produced iron into steel on the fuel fired open hearth.

It is a characteristic of iron producedjin the solid we that it will oxidize readily and that it; also a'sa high melting point. The atmosphere obtaining in the fuel fired open hearth furnaces is oxidizing to iron itself, in

consequence ofiwhich, when solid produced iron is attempted to be melted in such a furnace, it oxidizes before it melts.

I propose, therefore, to protect the E011 from the oxidizing influences in the furnace atmosphere to which end, broadly speaking, as

I render these influences ineifective in so far as the iron is concerned by the liltIOdllCtlOIl, into the charge, of Iothenmaterials, preferably pig iron; some of the constituents of whichare even more susceptible to the oxidizin'g influencesthan the iron.

In'carrymg out myinvention with the basic process of open hearth conversion, I

prefer to first cover the bottom of v the furnace with lime and then charge in a portion of the iron, after which I charge in a layer of pig iron, either inthe solid or fluid state. In either state it constitutes a layer interposed between the iron and the furnace atmosphere, shielding or protecting the iron from the oxidizing influence. This shield becoming progressively more effective in the case where pig in the solid state is used, as melting proceeds. The charge. thus introduced is melted, whereupon the remaining Application medranuar 10,1925. Serial ins-1,555;

portion-of. the iron, if any, is then charged into the fluid bath sinking under the slag that has already been formed, in consequence I'have found in the case of pig iron, that, the amount thereof should constitute from approximately 15V to approximately 25% of the total charge by' weight. While the upper limit may be exceeded, I have found it .best practice not -to"employ materially less than 15% of plg iron. 'Ihe pig iron in addition of which such portion of the charge of iron similarly shielded from the'oxidizingiliuence.

to its function of shielding the solid .pro-

duced iron from the oxidizing influences,

ing with the nature thereof. Thus, for ex--.

ample, .with ferro silicon I would employ anamount: very much less than 15%, probably 'in the neighborhood of to The foregoing is upon the assumption that mill scrap is not being utilized. When, however, Inillscrap must be taken care of, I include the scrapin the initial charge as before described. Irrespective of whether or not null scrap is charged with the solid produced iron, I employ the percentage of pig ironzabove set forth; that is to say, the pig iron,s'hould constitute frdin about to about of the. total charge.

In conversion by the acid process,-1 proceed along the lines above set forth, with the exception that I do not employ a lime floor covering. No floor covering may] be re'-.

quired, but sand or other siliceous material may be used to good jeifect if desired, or asmall layer of pig iron may be first charged on the hearth.

-When iron is produced in the solid state to convert with much less'destructive efl'ect ice from its ores resulting in the solid produced iron referred to, the earthy, mineral dross adheres to some extent to the iron nodules. The presence of such dross, however, is not necessarily objectionable in converting the iron on the fuel fired hearth. Therefore, it

is generally not necessary in carrying out a solid state by heat treatment in conjun;

tion fvithvsuitablo carbonaceous material, the reaction being carried on without fusion or melting of the ore. In short, the ore is re-. duced to the so-callcd solid produced iron without passing through the melting stage as in the usual blast furnace practice.

I claim: i 1. In the munufami'ir h 3 steel, the process which"includes-supplyiog e, charge of solid produced iron'to an o n hearth furnace,

covering such charge *imth pig iron so as to renderthc oxidizing. influence of the furnace atmosphere inefiective to the solid produced mm.

2. In the manufacture of steel, the process which includes supplying a charge of solid produced iron to an open hearth furnace, covering such charge with a protective layer of molten pig iron which is adapted to trickle down through said charge and dis solve the shine 3. In the manufacture of steel, the process which includes supplying a charge of solidproduced iron to an open hearth furnace,

covering such charge with a protective agent such as pig iron, ferro-silicon or the like. so as to render the oxidizing influence of the furnace atmosphere inefiectiye to the solid produced iron. I

In testimony whereof, I have hereunto signed m'y name a gMITH. 

